Dob owners: My gear-driven az & el controls permit smoother high-power viewing.

[Roy G. Biv]

I have dramatically improved the manual az/el motion of my Zhumell ten-inch Dob by incorporating easy to obtain and install off-the-shelf parts. I hope that these modifications will be of use to t hose Dob owners who are unhappy with jiggling images when using, for example, a 2.3 mm eyepiece.

I don’t think much narrative is necessary being that “a picture is worth a million words.” Besides, Dob owners will immediately recognize the rationale for the modifications.
For smoother azimuth movement all you need are these principal parts:
1. Cut and bolt a shorter-radius, wooden fixed-disk to the platform.
2. A bicycle chain and sprocket.

For smoother elevation movement:
1. Fashion and attach a wooden frame to the rocker box.
2. Get a 3/8" threaded steel rod, a threaded knob, and a pivot brace.
Included also, are pictures of other mods that may be of use.

I will be glad to respond to requests for more info.

Your northerly brother,

Roy G. Biv

[Dennis]

Nice job!

Cheers

Dennis

[Omaroo (Chris Malikoff)]

Great mod Roy. Not that I'm a Dob owner, but I've had a go on a few and recon that your idea here might just work for slo mo.

Whereabouts in Poughkeepsie are you? I used to live near Vasser College (the old IBM sound labs converted to a house) and also did a stint down in Paterson just of I-84 (before you get to Rte-22). I loved living in the Poughkeepsie area. I really miss Mohonk and New Paltz too. I used to practically live at Circuit City on Rte-9.

[middy]

Originally Posted by Dennis

Nice job!

Dennis, your old high school Physics teacher would be proud!

Nice job Roy. Bike chain and sprocket. What a great idea!

[Dennis]

Originally Posted by middy

Dennis, your old high school Physics teacher would be proud!

As would yours Andrew!!!

Cheers

Dennis

[rmcpb (Rob)]

Thankyou!! I have been working on a similar project but having problems with the friction drive system I have come up with. The bike chain is so simple and is just what I needed.

[gaa_ian (Ian)]

That's Awesome Roy !
Very inventive, and done with inexpensive off the shelf components.
Must be very smooth to use.
Cheers
Ian

[rmcpb (Rob)]

New related thread here.